<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <select id="colorSelect">
    <option>Red</option>
    <option>Green</option>
    <option>White</option>
    <option>Black</option>
  </select>
  <button onclick="button()">删除</button>
  <script>
    function button() {
      var obj = document.getElementById("colorSelect");
      var index = obj.selectedIndex;
      obj.options.remove(index);
    }

  </script>

</body>

</html>